1. Technical Field
The present disclosure relates to integrated optics, and particularly to an electro-optic modulator.
2. Description of Related Art
Electro-optic modulators, such as Mach-Zehner electro-optic modulators, change a refractive index of a branch of a Y-shaped waveguide (hereinafter the modulated branch) using a modulating electric field, utilizing an electro-optic effect. Thus, the modulator can alter a phase of lightwaves traversing the modulated branch. As a result, the lightwaves traversing the modulated branch have a phase shift and thus interfere with lightwaves traversing another branch of the Y-shaped waveguide (hereinafter the non-modulated branch). An output of the Y-shaped waveguide is modulated as the output depends on the phase shift, which in turn depends on the modulating electric field. To avoid too much insertion loss, a divergent angle between the branches of the Y-shaped waveguide is relative small. As such, the two branches are close to each other, which may cause crosstalk between the lightwaves traversing both branches of the Y-shaped waveguide.
Therefore, it is desirable to provide an electro-optic modulator, which can overcome the above-mentioned problems.